Towel dispensers are known and are shown in U.S. Pat. Nos. 3,647,159; 4,131,044; and 4,165,138. For example, Bump, U.S. Pat. No. 3,647,159, shows a towel dispenser having an automatic towel length controlling means and roll support tensioning means. The towel dispenser disclosed generally comprises a shell, means within the shell for rotatably supporting a roll of paper toweling, a frictional power roller engaging a paper web from the roll, and means for limiting the length of individual paper towels withdrawn from the dispenser. The latter means includes a first gearlike member rotatable with the power roll, a second gearlike member rotatable in response to rotation of the first gearlike member, a finger carried by the second gearlike member, a strap mounted for linear movement on the dispenser between a first position and a second position, an abutment surface carried by the strap in a position intersecting the excursion path of the finger when the strap is in a first position, a limit abutment carried by the strap in a position intersecting the excursion path of the finger when the strap is in the second position, means temporarily holding the strap in the second position and means urging the strap toward the first position. The strap is moved toward the second position by contact of the finger with the abutment surface in response to rotation of the second gearlike member.
Electronic towel dispensers are also known. U.S. Pat. Nos. 3,730,409; 3,971,607; 4,738,176; 4,796,825; and 4,826,262 each disclose electronic towel dispensers. For example, in Ratti, U.S. Pat. No. 3,730,409, a dispenser comprises a cabinet having a supply roll of paper towel therein and an electric motor-driven dispensing roll frictionally engaging the towel web for advancing it through a dispensing opening past a movable cutter. The cutter is biased to a normal rest position and is movable to a severing position in response to the manual cutting action by a user. The dispenser further comprises a control circuit including a normally closed start switch and a normally open ready switch connected in a series between the motor and an associated power source. The normally open stop switch is in parallel with the ready switch. Program apparatus is coupled to the cutter, the motor and the control circuit and is responsive to movement of the cutter to its severing position for opening the start switch and closing the ready switch. Movement of the cutter back to its normal rest position recloses the start switch to energize the motor. The program apparatus is responsive to operation of the motor for sequentially closing the stop switch then reopening the ready switch and then reopening the stop switch to de-energize the motor.
Finally, “hands-free” systems for controlling the operation of washroom fixtures such as water faucets, soap dispensers and towel dispensers are known. Examples of such hands-free systems are disclosed in U.S. Pat. Nos. 4,796,825; 5,031,258; 5,060,323; 5,086,526; and 5,217,035. In Hawkins, U.S. Pat. No. 4,796,825, an electronic paper towel dispenser is shown which permits paper towels to be dispensed from a supply roll by placing a hand or other object in front of a sensor located on the front of the supply cabinet. Dispensing of the paper towels is stopped when the hand is removed or when normal room lighting is not available. The dispensing of towels is controlled by a touchless switch for energizing a motor means.
The problem with prior hands-free electronic dispensers is that they require a source of electricity such as AC current from a plug-in wall outlet to power the hands-free mechanism. This can be dangerous to a user, especially when the dispenser is near a sink or other source of water. Another problem is that many prior hands-free dispensers are complicated devices which are expensive to manufacture and difficult to maintain in working order. Still another problem is that prior hands-free dispensers continue to dispense paper so long as the user's hand remains in front of the sensor. Also, if a change in ambient light occurs, prior hands-free dispensers have to be manually reset to adjust to a new light reference.
Therefore, it would be advantageous to provide improved towel dispensers for automatically dispensing a length of towel in response to the movement of an object such as a user's hands. In this manner, a user can avoid contact with viruses or bacteria on the dispenser left by prior users'hands. It would be further advantageous to provide energy-efficient hands-free dispensers which utilize light energy. It would also be advantageous to provide hands-free dispensers which are simple in design, safe and easy to use. It would be even further advantageous to provide hands-free dispensers which are inexpensive to manufacture and free from problems such as inoperability due to jamming or changes in ambient light conditions.